With MailChimp's Ecommerce functionality you can track visitors to your website from your email campaigns, capture order information and then pass it all back to MailChimp.
This allows you to view which campaign generated which purchases and set up powerful list segments based on the purchase activity of your subscribers.
As of version 4.0, MailChimp for WordPress supports full Ecommerce integration including Abandoned cart and Order Notifications.
To start adding orders to MailChimp when they're created, go to MailChimp for WP > Ecommerce and connect your store to a list.".
Tracking new purchases
Now you have Ecommerce enabled, every time a new purchase is made the order data will automatically be sent to MailChimp. If the customer was coming from one of your email campaigns, the plugin will automatically detect this and send the campaign information to MailChimp as well.
Orders aren't sent to MailChimp during checkout. Whenever someone places an order, the plugin creates a task which will be picked up at a later time. This means that the performance impact on your checkout is literally close to zero.
It may take a while before order information shows up in your MailChimp account, but normally this should not take longer than an hour.
Recording past purchases
Right after enabling Ecommerce and connecting your store, it will ask you to add all past orders to MailChimp.
Clicking the link in that notice will take you to a page where you can track all past orders by clicking the Record Orders button.
Because all work is performed in the background, debugging Ecommerce may seem hard.
Luckily, version 3.1 also comes with a debug log. The debug log shows all kind of interesting events (like when an order was added to MailChimp) so you can see what the plugin has been up to in your absence.
Please read our article on enabling debug logging for more information.